<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>Title</title>
</head>
<body>
<!--
    action:form表单提交的请求地址
    method:请求方式，指定为post
-->
<form action="Servletdemo4" method="post">
  <input type="text" name="username">
  <input type="password" name="password">
  <input type="submit">
</form>
</body>
</html>